History of the Peloponnesian War

And if that city is taken, the whole of Sicily also is in their possession, and Italy, too, straightway; and the danger which I just now mentioned as impending from that quarter, would in no long time fall upon you. Let no one then think that he is deliberating about Sicily alone, but about the Peloponnese also, unless you quickly adopt these measures;

unless, I mean, you send thither on board ship such a body of troops, as, after working their own passage, shall immediately act as heavy infantry; and also, what I consider to be still more serviceable than troops, a Spartan as commander, both to discipline their present forces, and to compel those who are unwilling to serve. For so the friends you already have will feel the greater confidence, and those who are doubting between the two sides will more fearlessly join yours. You must also carry on hostilities here in a more decisive manner; that the Syracusans, convinced that you take an interest in them, may offer the greater resistance;

and that the Athenians may the less easily send reinforcements to their troops. And for that purpose you must fortify Decelea, in Attica; a blow of which the Athenians have always been most afraid, and the only one which they think they have not experienced in the present war.

And in that way would one most surely hurt his enemies, if, acting on certain information, he should inflict upon them those things which he knows them to fear most: for it is but reasonable that every people should know most accurately its own dangers, and fear them accordingly. But with regard to the difficulties which, while you benefit yourselves, you will create for your opponents by thus fortifying the place, though I pass over many, I will briefly mention the chief.